Employee Benefit Plans and Other Postretirement Benefits (Schedule Of Net Periodic Benefit Cost Recognized In Accumulated And Other Comprehensive Income) (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	$ (10,007)
Net actuarial loss	470,950
Amounts included in other comprehensive income, net of tax	460,943
Pension and SERPA Benefits
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	(4,136)
Net actuarial loss	450,754
Amounts included in other comprehensive income, net of tax	446,618
Postretirement Health Coverage
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	(5,871)
Net actuarial loss	20,196
Amounts included in other comprehensive income, net of tax	$ 14,325